Polyphase-motor cascade driving system.



C. DE KANDO. Y

POLYPHASE MOTOR CASCADE DRIVING SYSTEM.

AYPLIOATION FILED DEO.13, lane.

1 ,O4 6,6O1 Patented Dec. 10, 1912.

2 SHEETS-SHEET 1.

0. DE KANDO.

POLYPHASE MOTOR CASCADE DRIVING SYSTEM. APPLICATION FILED DBO. 13, 1906.

1,046,601 Patented Dec. 10, 1912 2 SHEETSSHEET 2.

WITNESSES INVENTOR araw... 44M VI ATTORNE Y8 of two motors connected in however to enable cascade.

UNITED sTATns PATENT oinnon.

COLOMAN DE KA NDG, 0F BUDAPEST, AUSTRIA-HUNGARY.

POLYPHASE-MOTGR CASCADE DRIVING SYSTEM.

To all whom it may concern:

Be it known that I, CoLoMAN on KANDO, a subject of the King of Hungary, and resi' dent of Felso erdosor 12, Budapest, in the Empire of Austria-Hungary, have invented certain new and useful Improvements in or Relating to Polyphase-Motor Cascade Driving Systems, and hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the arrangement for connecting two or more three-phase-motors, for the purpose of regulating the speed in electric railways, which enables high tension motors to be worked either in cascade connection or independently of each other.

In the drawings Figured is a diagram cascade relation. Fig. 2 is a similar diagram with the motors in parallel. Fig. 3 is a connection diagram showing more in detail an arrangement of motors and switches in accordance with my invention.

The problem to be solved is as follows: Two three-phase motors I and II (Fig. l) are given. The source of current is a high pressure line 1, 2, 3 of say 3000 volts.

a. The'two motors are to be started and worked in cascade connection by means of the starting switch or resistance W (Pig. 1).

Z). The two motors are to be started and worked switched together in parallel or in dependently of each other (Fig. 2).

It is well known that starting switches or resistances can be made in p notice only for considerably lower pressures than those that can be used for current collectors of the line wires, or for the direct feeding of motors. For instance, practical installations can be shown in which the motors receive a pressure of 3000 volts from the line wire, while the secondary pressure of the'motors must be considm'ably lower, for instance not over 600 volts, in order to enable the connection to be effected (Fig. 2). In order connection to be carried out, the primary winding B'of the motor II would also have to be calculated for 000 volts, which, however, would then make it impossible to connect as shown in Fig. 2, as the primary winding E, ii calculated for 600 volts, would not be suitable for connecting direct to high pressure lines 1, 2, 3, of 3.000 volts. In order to overcome Specification of Letters Patent.

Application filed December 13, 1906. Serial No.

Patented Dec. 10, 1912.

this difiiculty, it had already been suggested to reduce the pressure in a suitable 1nanner either for the second motor or for the starting resistance by switching in a transformer. is, however, a complicatedmatter, and it is ofgreat importance in railway working to economize as much weight and space as possible, and to do away with any causes of disturbance, and therefore it is often desirable to avoid the arrangement of such a transformer, or of several of them, when more than one motor couple is to be used.

The subject of my invention is an arrangement for connecting or switching, which on ables the problem mentioned in the begin nmg to be solved, without any transformer being used. In the new switching arrangement the chief feature is that the separate phases of the high pressure winding of the motors are divided into several sections which are connected with a suitable switch in such manner that, when the motor is to be connected to the high pressure line, they are switched in series, but when the motor, as a driven motor, is to be supplied from the lower secondary pressure of the loading or driving motor, they are switched in parallel. In view, of the great difference between the primary and secondary pressure, an extreme subdivision of the winding would be required, thus for instance with a primary pressure of 3.000 volts and asecondary pressure of about 600 volts, it would be necessary to have a quintuple sub-division.

I have provided means for overcoming the objectional features above enumerated, an embodiment of which is illustrated in the accompanying drawings.

Fig. 3 shows a connection diagram of a construction according to this invention. for

two three-phase motors I, II.

The stator B of the motor II is wound for high pressure, the parts at, y m 3 m, 3 corresponding to the three phases. The single phases of the stator winding are divided into several sections, in the drawing into three, each, the said sections being connected to the switches S S S 'By means of these switches, the three sections of the phases can be connected in series or in parallel, and in such manner that, when the switches S S S are in the positions shown in full, the sections of each'phase are con" nected in series, while the position of the said switches shown dotted corresponds to The arrangement of a transformer I theparallel connection of the section. With reference to the phase W, 3 the circuit for instance, for the position of the switch S, shown in full lines, is as follows: m p 6 f p g so that the current passes consecutively through the coils p p 11 while in the dotted position the ends 6 and 8 of the coils p p, are connected at +1: and 9 to 03 and the other ends 5 and 7 of the coils 1) p are connectedat 5 10 and 7 11 to y, so that thethree coils are connected in parallel. The same change of connection can be effected by the switch S or S in the phase m 3 or 00 y. The ends of the single phases of the stator winding are guided to a switch U, the ends y ,-y y, being connected to the switch levers 12, 13 14, while the ends .70 w or m are connecte to the contacts 15 16 or 17. The contacts .18 19 and 20 are electrically connected together by 21.

When the switch shown in full lines, the ends g, 3 3 of the "three phases are connected together by 12 18 or' l3 19 or 14 20 and. 21, so that the phases are connected in the shape of a star. When the switch U is brought into the dotted position, y is connected by 12 and 15 to w; y by 13 and 16 to w? and finally y by 14 and.17 to a, so nection is produced. The switches S S S and U are preferably mechanically connectbe operated simultaneously.

means of the switch 2 lectors K which collect the current from the mary windin high pressure line 1 2 3, can be connected by means of the switch H, either to the pri- A of the motor I, or to the primary win ing B of the motor II, accordmg as the one or the other motor is to be supplied with electricity direct from the high pressure line. The switch 2 when in its position shown in full lines, connects the rotor a of the motor I, to the resistance W, while in the dotted position of the switch Z, the rotor of the motor I is connected to the poles m 00 w of the stator winding B of the motor II.

WVhen it is desired to start the motor I, the rotor of the same is connected by means to the switch-Z to the startin resistance W. If'the motor II is to work in ependently of I, then, after movin the switches S S shown in full lines, the motor is started, by means of the starting resistance W When the two motors have the same number of poles, they can be both connected simultaneously to the high pEressure line, as diagrammatically shown in ig. 2 but if the number of their polesis different, they can be switched in alternately for obtaining two different speeds. If for obtaining asmaller U.is in the position! that a triangle conondaries wo'un wound or line pressure and secondaries for the switch H, and with a and U in the positions speed, the motor II is to be connected to the motor I in cascade, the switches Z S S S and U are moved into the position shown dotted. In this way, on the one hand, the rotor of the motor I is connected to the stator of the motor II, and, on the other hand, the section of separate phases of the stator winding are connected in parallel, and thus the triangle connection produced, so that the stator winding B, wound for the high pressure, can be supplied with current by the low pressure current of the rotor a. As the switch Z is operated simultaneously with the switches S S S and U, all the switches can be connected mechanically or operated by means of relays or by compressed air simultaneously or in a given sequence. The cascade connection can also be produced by connecting the'rotor a to the rotor 11, and the stator B of the motor II to the starting resistance after the parallel and triangle connection has been eflected as indicated in Fig. 1. Normally it is suificient to provide only the stator winding of one motor II with the device for switching in series and parallel or star and triangle, but the two motors could also be built in the same way. The new switching device can of course be applied in a correspondingmanner to more than two motors. I

Having now described my invention what I claim is 1 1. In an induction-motor driving system, induction-motors having their primaries insulated for hi h pressure and their see- (I for low pressure, the rimar'y of one .being wound in sections efini-tely related to the pressure of the secondary element, a rheostat suitable forthe pressure of the secondary, means for grouping the primary sections forconnection either for the high pressure or for the rheostat pressure, means for connecting said sectioned primary to the hi h pressure line and means for connecting the secondary of said other motor either to said sectioned primary or to said rheostat.

'2. In an induction-motor driving system,

a high ressure line, motors with primaries 2i lower pressure, the primer windin of one or more motors being su divided into sections definitely related to the secondary pressure, switches for grouping the subdivisions oi the primary windings for con: nection alternately for the line pressure and for the secondary pressure, means for connecting such motor as a secondary motor in a cascade system when its windings are rouped for secondary or connectin the motor directly to' line when its windings are grouped for line pressure. 3. In an induction-motor drivingsystem, two or more induction motors having their pressure, and means 5 nested in one relation to cade group.

Crorrectio Letters Patent No. 1,046,601.

- primaries insulated for high pressure and their secondaries wound for a lower pressure, the primaries of one of said motors being wound in sections adapted when conwork efliciently at the high pressure and in another relation to work efficiently at the pressure of the sec ondary of another motor, means for group ing the sections of said primary winding at will for either pressure and means for connesting the motor with its subdivided windings grouped for low pressure as secondary motor in cascade with a motor having its windings suited to high pressure.

In an induction-motor driving system, two or more induction motors having their primaries wound for high pressure and their secondaries for a definitely related low pressure, one of said primary windings being 5. In an induction motor driving system, a high pressure line, three-phase motors having their primaries adapted for connec t-ion to said line when the phases are arranged instar relation, one or more of said motors having each of its primary windings subdivided into equal sections and the secondaries of'all the motors wound for the pressure of each of said sections, switches connecting said sections in series and phases in star relation for operation from the high pressure line and said sections in parallel and the phases in delta relation for operation in cascade, and means for connecting and controlling the motors in cascade, the motor having subdivided windings acting as secondary motor in the cascade group.

In testimony whereof I aflix my signature to this specification, in the presence of two divided into sections, and means for conwitnesses. meeting said sections in parallel in each I COLOMAN DE KANDO. phase and means for connecting the so eon- Witnesses:

nected motor as secondary motor in a cas- EUGENE HARRANY,

CHARLES E. MATINE.

It is hereby certified that in Letters Patent No. 1,046,601, granted December 10,

1912, upon the application of Coloman de Kando, of Budapest, Austria-Hungary,

' for an improvement in Polyphase-Motor Cascade DrivingSystems, an error Iappears in the printed specification requiring correction as follows: Page 2, line 35, for the Word switch read resistance," and that the said Letters Patent should be read with this correction therein that the same may contorm to the record of the case in the Patent Office. I

238th day of January, A. 1913.

(J. (J. BILLINGS,

Act ug Chmmz'ssz'oner of Patents.

Signed and sealed this [SEAL] 

